1. Field of the Invention
The present invention relates generally to a letter input method for a mobile terminal and, more particularly, to a method of inputting a letter through extraction of proposed letter sets corresponding to key input data in a mobile terminal having a keypad in which several letters are allocated to each key.
2. Description of the Related Art
In general a keyboard, a typical input device of a computer, has a single key arrangement in which a single letter is allocated to each key. A mobile terminal such as a mobile phone or a Personal Digital Assistant (PDA), however, has in general a multiple key arrangement in which several letters are allocated to each key, since a keypad is relatively limited in space.
FIGS. 1A and 1B are schematic views showing two types of keypads of a conventional mobile terminal. The keypad shown in FIG. 1A has what is called a 3×4 key arrangement similar to a telephone key configuration, whereas the keypad shown in FIG. 1B has what is called a QWERTY key arrangement following a keyboard key configuration. In the former keypad, each key has three or more letters allocated thereto. Similarly, in the latter keypad, each key has two or more letters allocated thereto.
To input a letter in such a conventional mobile terminal, a user has to often repeatedly press a key to which a letter for input belongs. For example, in case four letters ‘PQRS’ are allocated to a certain key, a user must press the same key twice to input the second letter ‘Q’, and must press the same key four times to input the fourth letter ‘S’. Accordingly, such a conventional letter input method may waste time, due to repeated key presses, and further, this may sometimes cause some input errors.
To solve these problems, other letter input methods have been introduced that employ a word dictionary embedded in a mobile terminal. According to these methods, similar words are extracted from the dictionary by comparing key input data with the dictionary and are offered on a display screen for user's choice. These conventional methods may, however, have a limitation that such words offered for the user's choice are only the words contained in the dictionary. Additionally, these methods may fail to efficiently display a number of similar words on the display screen.